Swarm (Japanese: むしのしらせBug Notification) is an Ability introduced in Generation III. Twenty-four Pokémon can have this Ability, all of which are Bug types.

Effect

In battle

When a Pokémon with Swarm uses a Bug-typemove, the power will increase by 1.5× if the user has less than or equal to ⅓ of its maximum HP remaining.

Outside of battle

From Pokémon Emerald onwards, if the Pokémon leading the party has Swarm, the chance of encountering wild Pokémon increases. In Pokémon Emerald, this Ability also increases the rate in which the cries of wild Pokémon could be heard on the field.